Water is the largest single component of the human body. It constitutes about 60% of body weight in young adult males and 50% in young adult females. Water constitutes 93% of plasma and 97% of interstitial fluid.
Intracellular water is the major component of cells, except fat cells, and constitutes 73% of the weight of metabolically active cells of muscle and viscera.
Water Balance- Too much sodium creates lowered potassium, and the reverse is also true. Too much of either mineral will create an imbalance in the distribution of fluids between the cellular walls. Sodium is thought to cause high blood pressure. The causes of hypertension formerly were not definitively known; indirect evidence suggests, however, that several aspects of nutrition, especially the ingestion of excessive amounts of sodium, may be involved.
Potassium is stored almost entirely within the lean tissues, where it helps maintain fluid volume. Diuretics, fasting, alcohol, diarrhea and vomiting can decrease the absorption and utilization of this mineral.